Merge lp:~charlesk/indicator-datetime/lp-1405806-improve-clock-change-detection-rtm-14.09 into lp:indicator-datetime/rtm-14.09

[Charles Kerr]

change the WallClock to detect time changes from TFD_TIMER_CANCEL_ON_SET, e.g. when ntp<-->manual is toggled

backport http://bazaar.launchpad.net/~indicator-applet-developers/indicator-datetime/trunk.15.04/revision/398 to detect user-initiated manual clock changes for bug #1405806

trunk MP is at https://code.launchpad.net/~charlesk/indicator-datetime/lp-1405806-improve-clock-change-detection/+merge/249433; its description and checklist applies here.

[Ted Gould (ted)]

review: Approve

=== modified file 'src/clock-live.cpp'
--- src/clock-live.cpp	2014-09-16 19:55:30 +0000
+++ src/clock-live.cpp	2015-02-13 20:32:42 +0000
@@ -20,6 +20,15 @@
 #include <datetime/clock.h>
 #include <datetime/timezone.h>
 
+#include <glib-unix.h> // g_unix_fd_add()
+
+#include <sys/timerfd.h>
+#include <unistd.h> // close()
+
+#ifndef TFD_TIMER_CANCEL_ON_SET
+ #define TFD_TIMER_CANCEL_ON_SET (1 << 1)
+#endif
+
 namespace unity {
 namespace indicator {
 namespace datetime {
@@ -28,33 +37,6 @@
 ****
 ***/
 
-namespace
-{
-
-void clearTimer(guint& tag)
-{
-    if (tag)
-    {
-        g_source_remove(tag);
-        tag = 0;
-    }
-}
-
-guint calculate_milliseconds_until_next_minute(const DateTime& now)
-{
-    auto next = g_date_time_add_minutes(now.get(), 1);
-    auto start_of_next = g_date_time_add_seconds (next, -g_date_time_get_seconds(next));
-    const auto interval_usec = g_date_time_difference(start_of_next, now.get());
-    const guint interval_msec = (interval_usec + 999) / 1000;
-    g_date_time_unref(start_of_next);
-    g_date_time_unref(next);
-    g_assert (interval_msec <= 60000);
-    return interval_msec;
-}
-
-} // unnamed namespace
-
-
 class LiveClock::Impl
 {
 public:
@@ -70,12 +52,31 @@
             setter(m_timezone->timezone.get());
         }
 
-        restart_minute_timer();
+        m_timerfd = timerfd_create(CLOCK_REALTIME, 0);
+        if (m_timerfd == -1)
+        {
+            g_warning("unable to create realtime timer: %s", g_strerror(errno));
+        }
+        else
+        {
+            reset_timer();
+
+            m_timerfd_tag = g_unix_fd_add(m_timerfd,
+                                          (GIOCondition)(G_IO_IN|G_IO_HUP|G_IO_ERR),
+                                          on_timerfd_cond,
+                                          this);
+        }
+
+        refresh();
     }
 
     ~Impl()
     {
-        clearTimer(m_timer);
+        if (m_timerfd_tag != 0)
+            g_source_remove(m_timerfd_tag);
+
+        if (m_timerfd != -1)
+            close(m_timerfd);
 
         g_clear_pointer(&m_gtimezone, g_time_zone_unref);
     }
@@ -92,6 +93,61 @@
 
 private:
 
+    void reset_timer()
+    {
+        struct itimerspec timerval;
+        // set args to fire at the beginning of the next minute...
+        int flags = TFD_TIMER_ABSTIME;
+        auto now = g_date_time_new_now(m_gtimezone);
+        auto next = g_date_time_add_minutes(now, 1);
+        auto start_of_next = g_date_time_add_seconds(next, -g_date_time_get_seconds(next));
+        timerval.it_value.tv_sec = g_date_time_to_unix(start_of_next);
+        timerval.it_value.tv_nsec = 0;
+        g_date_time_unref(start_of_next);
+        g_date_time_unref(next);
+        g_date_time_unref(now);
+        // ...and also to fire at the beginning of every subsequent minute...
+        timerval.it_interval.tv_sec = 60;
+        timerval.it_interval.tv_nsec = 0;
+        // ...and also to fire if someone changes the time
+        // manually (eg toggling from manual<->ntp)
+        flags |= TFD_TIMER_CANCEL_ON_SET;
+
+        if (timerfd_settime(m_timerfd, flags, &timerval, NULL) == -1)
+            g_error("timerfd_settime failed: %s", g_strerror(errno));
+    }
+
+    static gboolean on_timerfd_cond (gint fd, GIOCondition cond, gpointer gself)
+    {
+        auto self = static_cast<Impl*>(gself);
+
+        int n_bytes = 0;
+        uint64_t n_interrupts = 0;
+        if (cond & G_IO_IN)
+            n_bytes = read(fd, &n_interrupts, sizeof(uint64_t));
+
+        if ((n_interrupts==0) || (n_bytes!=sizeof(uint64_t)))
+        {
+            auto now = g_date_time_new_now(self->m_gtimezone);
+            auto now_str = g_date_time_format(now, "%F %T");
+            g_message("%s triggered at %s.%06d by GIOCondition %d, read %zd bytes, found %zu interrupts",
+                      G_STRFUNC, now_str, g_date_time_get_microsecond(now),
+                      (int)cond, n_bytes, n_interrupts);
+            g_free(now_str);
+            g_date_time_unref(now);
+
+            // reset the timer in case someone changed the system clock
+            self->reset_timer();
+        }
+  
+        self->refresh();
+        return G_SOURCE_CONTINUE;
+    }
+
+    /***
+    ****
+    ***/
+
     void setTimezone(const std::string& str)
     {
         g_clear_pointer(&m_gtimezone, g_time_zone_unref);
@@ -103,33 +159,17 @@
     ****
     ***/
 
-    void restart_minute_timer()
+    void refresh()
     {
-        clearTimer(m_timer);
+        const auto now = localtime();
 
         // maybe emit change signals
-        const auto now = localtime();
         if (!DateTime::is_same_minute(m_prev_datetime, now))
             m_owner.minute_changed();
         if (!DateTime::is_same_day(m_prev_datetime, now))
             m_owner.date_changed();
 
-        // queue up a timer to fire at the next minute
         m_prev_datetime = now;
-        auto interval_msec = calculate_milliseconds_until_next_minute(now);
-        interval_msec += 50; // add a small margin to ensure the callback
-                             // fires /after/ next is reached
-        m_timer = g_timeout_add_full(G_PRIORITY_HIGH,
-                                     interval_msec,
-                                     on_minute_timer_reached,
-                                     this,
-                                     nullptr);
-    }
-
-    static gboolean on_minute_timer_reached(gpointer gself)
-    {
-        static_cast<LiveClock::Impl*>(gself)->restart_minute_timer();
-        return G_SOURCE_REMOVE;
     }
 
 protected:
@@ -139,7 +179,8 @@
     std::shared_ptr<const Timezone> m_timezone;
 
     DateTime m_prev_datetime;
-    unsigned int m_timer = 0;
+    int m_timerfd = -1;
+    guint m_timerfd_tag = 0;
 };
 
 LiveClock::LiveClock(const std::shared_ptr<const Timezone>& timezone_):

=== modified file 'tests/manual'
--- tests/manual	2015-01-21 21:33:53 +0000
+++ tests/manual	2015-02-13 20:32:42 +0000
@@ -137,6 +137,12 @@
 		<dd>The calendar event notification should play a sound.</dd>
 </dl>
 
+Test-case indicator-datetime/manual-time
+<dl>
+	<dt>In System Settings > Time & Date, manually change the time to an arbitrary time.</dt>
+		<dd>The indicator's timestamp should change right after the time manual time is set.</dd>
+</dl>
+
 <strong>
     If all actions produce the expected results listed, please <a href="results#add_result">submit</a> a 'passed' result.
     If an action fails, or produces an unexpected result, please <a href="results#add_result">submit</a> a 'failed' result and <a href="../../buginstructions">file a bug</a>. Please be sure to include the bug number when you <a href="results#add_result">submit</a> your result</strong>.